FIELD OF THE INVENTION
This invention relates in general to boilers, and in particular to a new and useful atmospheric gas boiler which includes three spaced apart vertically elongated parts defining vertical gas passes there between in a lower area which communicates three new gas passes which together with the gas passes defines a furnace area into which burner lances discharge.
The invention particularly concerns an atmospheric gas boiler with two vertically arranged terminal pieces and at least one middle piece arranged between them as well as burner lances arranged in the lower part of the gas boiler, whereby the elements of the boiler through which hot water flows have a furnace with secondary heating surfaces adjoining thereon.
Such gas boilers are used primarily as central heating boilers. There is no blower in an atmospheric gas boiler. Therefore, the furnace has an opening for ingress of secondary air, while the primary air is suctioned in through a mix pipe of the burner or the burner lances.
In an atmospheric gas boiler of this type, the middle piece or pieces extend only in the region of the secondary heating surfaces and terminate above the furnace. Hence, relatively high flame and exhaust gas temperatures can arise in the furnace, thereby favoring the formation of NOX.